Linux tmpfs (Was: [OpenAFS] Solaris 10u6: ZFS cache?)

Brandon S. Allbery KF8NH
Fri, 14 Nov 2008 13:28:44 -0500

On 2008 Nov 14, at 7:18, Chas Williams (CONTRACTOR) wrote:
> In message <5FB03AFA-8CA1-4B39- 
>>,"Brandon S. Allbe
> ry KF8NH" writes:
>> It used to be said (back when warlord was maintaining linux-afs and
>> Transarc 3.4a was the main release) that the memcache was much less
>> efficient than the disk cache and that it was better to use disk  
>> cache
>> in a ramdisk.  Both have been pretty thoroughly overhauled since  
>> then,
>> though.
> "efficient" isnt meaningful without context.  memcache does use quite
> a bit of host memory.  if your system is short on memory, memcache is
> not for you.  however, memcache outperforms diskcache is most cases
> (ignoring say rereads over a link with high latency).

At the time memcache was an unoptimized linked list, IIRC, and  
performance simply stank.  It was worse than disk cache.

brandon s. allbery [solaris,freebsd,perl,pugs,haskell]
system administrator [openafs,heimdal,too many hats]
electrical and computer engineering, carnegie mellon university    KF8NH